During pregnancy and lactation, folate status is important because folate requirements increase during the periods as well as maternal folate status influences on pregnancy outcome and human milk folate; especially folate deficiency around periconceptional period may induce neural tube defects(NTDs) of fetus. There have been a plenty of evidences that maternal folate status deteriorates during pregnancy of fetus. There have been a plenty of evidences that maternal folate status deteriorates during pregnancy and lactation if folate needed is not sufficiently provided. The Public health Service of the United States recommends all child-bearing is not sufficiently provided. The Public Health Service of the United States recommends all child-bearing women to intake 0.4mg of folate daily, and the Food and Drug Administration the folate status of child-bearing women and to reduce the rate of occurrence of NTDs. Many authors have insisted that the current recommended dietary allowances of folate for Americans are too low to maintain good folate status. There are little data about Korean folate status including pregant and lactating women. A couple of reports indicated that the folate intakes of Korean pregant and lactating women are below the Korean RDAs of folate and serum folate levels of them are subnormal. The authors pregnant and lactating women. Therefore, it is worth to review the assessment methods of folate status of pregnant and lactating women, folate RDAs for them, the relationships between maternal folate status and pregnancy outcome as well as human milk folate, the methods to increase folate intake, and the problems of large dose of folic acid supplementatiion.